Bd,s → γℓ ℓ ¯ decay with an energetic photon

Martin Beneke, Christoph Bobeth, Yu Ming Wang

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24 Scopus citations


We calculate the differential branching fraction, lepton forward-backward asymmetry and direct CP asymmetry for Bd,s → γℓ ℓ ¯ decays with an energetic photon. We employ factorization methods, which result in rigorous next-to-leading order predic- tions in the strong coupling at leading power in the large-energy/heavy-quark expansion, together with estimates of power corrections and a resonance parameterization of sub- leading power form factors in the region of small lepton invariant mass q2. The Bd,s → γℓ ℓ ¯ decay shares features of the charged-current decay Bu → γℓ ν¯ ., and the FCNC decays B → K(∗)ℓ ℓ ¯. As in the former, the leading-power decay rates can be expressed in terms of the B-meson light-cone distribution amplitude and short-distance factors. However, similar to B →K(∗)ℓ ℓ ¯ , four-quark and dipole operators contribute to the Bd,s → γℓ ℓ ¯ decay in an essential way, limiting the calculation to q2 ≲ 6 GeV2 below the charmonium resonances in the lepton invariant mass spectrum. A detailed analysis of the main observables and theoretical uncertainties is presented.

Original languageEnglish
Article number148
JournalJournal of High Energy Physics
Issue number12
StatePublished - Dec 2020


  • Heavy Quark Physics
  • Perturbative QCD
  • Resummation


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